1. Field of the Invention
The present invention relates to a technique for executing image data compression processing which compresses image data obtained by inputting a document from, for example, a scanner for respective predetermined blocks, and restoration processing of compressed data for respective blocks into image data and, more particularly, to a technique for correcting a density and color for an even color part in image data restoration processing.
2. Description of the Related Art
Image data input by, for example, a scanner is often input to have a different density and color, even on a part that is printed to have even density and color on a document, which is caused by floating of the document and a light amount of unevenness of a light source that illuminates the document. The unevenness of density and color stand out as image deteriorations when input image data is printed.
Conventionally, when the density unevenness and color unevenness are corrected, input image data is displayed on, for example, a monitor, and is corrected according to instructions of a part to be corrected and correction processing contents designated by an operator (see Japanese Patent Laid-Open No. 2000-278528). That is, various manual settings are required.
When the unevenness correction is to be automatically executed, recognition processing of parts to be corrected and correction amounts has to be executed for all data included in original image data so as to recognize parts to be corrected and how to correct these parts. After that, processing for correcting all data included in the original image data is executed again based on the recognized information.
As described above, when the density unevenness and color unevenness are to be corrected by the conventional method of manually designating a part to be corrected and correction method, a long processing time is required for correction processing as well as many hardware resources (equipments).
In the aforementioned automatic correction method, two processes, that is, the recognition processing and correction processing are required for all data included in an original image. Hence, in case of hardware implementation, a large-scale processing circuit and a considerable processing time are required.
Even in case of software implementation, the processing require a long processing time.